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Nicotine Rescues Brain Cells

- Mar 16 2004

Inflammation protection added to list of ways it fights such diseases as Alzheimer's and Parkinson's By Gabe Romain, Betterhumans Staff

In yet another study underscoring nicotine's ability to protect against brain diseases such as Parkinson's and Alzheimer's, researchers have discovered that it stops inflammation that kills brain cells.

It does this, researchers at the University of South Florida College of Medicine in Tampa have shown, by stopping normally friendly cells called microglia from becoming harmful.

"We propose that nicotine's ability to prevent overactivation of microglia may be an additional mechanism underlying nicotine's neuroprotective properties in the brain," says researcher Douglas Shytle.

Mental protection

While the health risks associated with nicotine are well known, many studies have shown that it can enhance cognitive abilities such as memory and concentration.

For example, researchers have found that nicotine patches can boost recall in seniors with mild memory loss.

Studies have found that such benefits stem from nicotine's ability to mimic acetylcholine, a neurotransmitter that plays a large role in learning and memory.

Similar to turning up the volume of a radio signal, nicotine enhances the volume of brain signals by causing an increase in neurotransmitters depleted in people with such diseases as Alzheimer's and Parkinson's.

Best friend to worst enemy

The study by Shytle and colleagues suggests that nicotine may also protect brain cells by suppressing the damaging effects of hyperactive microglia.

Normally, microglia maintain neurons and help to wipe up excess beta amyloid, a protein that accumulates in the brain with aging and is linked with some brain diseases.

"Microglia can be your best friend or your worst enemy depending on the signals they receive," says Shytle. "The analogy is that you keep talking to them they will take care of you, but if you stop talking they are more likely to get aggressive and have a toxic effect on the brain."

The researchers think that acetylcholine acts as an anti-inflammatory that prevents microglia from attacking the brain.

When neurons that communicate using acetylcholine fade, microglia become hyperactive and cause chronic inflammation that destroys brain cells.

Benefits without side-effects

Because nicotine may act like acetylcholine, it may send a signal to suppress microglia and limit brain inflammation, the researchers say.

"This finding lets us explore a new way of looking at neurodegenerative diseases like Alzheimer's," says researcher Jun Tan.

An increased understanding of nicotine's protective role against brain diseases will also allow researchers to build drugs that mimic its actions without its harmful side effects, such as addiction.